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Limitations

This page describes several limitations in the current version of Vanguard.

Assumptions​

  • Vanguard operates on the Yul IR code of non-abstract Solidity smart contracts. It cannot analyze abstract contracts, since solc will not generate code for them.
  • Because it is not possible in general to know what code may be invoked by an external call, Vanguard makes conservative assumptions about the side effects of each external call that it cannot resolve. For example, if a call target is not restricted to concrete contracts known to Vanguard, then Vanguard will assume the call target may reenter, modify other contract state, etc.

Unsupported Features​

  • Not all inline assembly is supported. Some inline assembly patterns may cause Vanguard to crash, although the Vanguard team has tried to minimize these occasions.
  • Reasoning about delegatecall (such as when making calls to external library functions) is limited. For example, detectors will not recognize state modifications made in external library functions.
  • Vanguard does not fully support struct fields, and it currently treats reads/writes to a single field as reading/writing from the entire struct.
  • Vanguard does not fully support reasoning about specific array indices. Reads/writes to a single index will be treated as a read/write to the entire array.
  • Projects that use non-standard storage layouts are not fully supported by the detectors in Vanguard; such non-standard locations will be treated as "unknown" locations, resulting in additional false negatives and false positives.